1. Field of the Invention
The invention relates generally to a fluid coupling to connect a fluid source line to a fluid supply line. More particularly, the invention relates to a gladhand for coupling the fluid lines of a tractor-trailer brake system. The gladhand has a swivel connection and comprises an internal valve to control the flow of fluid therethrough.
2. Description of the Related Art
Braking systems for tractor-trailers are typically pneumatic and rely on an air source located on the tractor. Air supply lines deliver air from the source to the braking system components on the trailer or trailers and comprise various types of hoses and couplings. Such hoses, couplings, and the like have standardized interconnections because the tractor-trailer is a modular assembly, wherein the trailer can be viewed as an interchangeable component. A single tractor can link to any trailer and can pull more than one trailer at a time, depending on the size and weight of the trailers. Therefore, the pneumatic braking system of a trailer must be able to communicate with that of any tractor, and, likewise, trailers must be able to connect with each other.
An example of a standardized coupling is a gladhand, which is well-known in the art and is designed to mate and seal with another gladhand to permit fluid communication between a trailer and a tractor or between trailers. Gladhands can be located on either the front or rear end of a trailer. A gladhand on the front of a trailer can be joined with the air source on the tractor. When located on the rear of a trailer, a gladhand is used for connection to another trailer.
An inline shutoff is normally located in the pneumatic line upstream of the gladhand at the rear of the trailer. If an additional trailer is not employed, the inline shutoff valve is closed to prevent the escape of the air through the rear gladhand. However, even if the inline valve is in the off position, the unconnected gladhand outlet is susceptible to contamination by bugs, dirt, and other debris, especially from the debris cloud formed by the moving trailer. The contamination can enter the air flow path of the brake system when the inline valve is later opened, which can be detrimental to the performance of the brake system. Additionally, when a trailer is not in tandem with a tractor, it often sits in an outdoor trailer yard. As a result, any gladhands on the trailer are exposed to potential contaminants in the environment.